In a relay system, when relays are installed, a network management system (NMS) server for monitoring each relay is installed together with the relays. According to a conventional art, in order to connect a BTS interface unit (BIU) of each relay to the NMS server, a GUI for local is installed in each BIU at a local place, and a manager directly performs an Internet protocol (IP) setup operation. Therefore, there is a an inconvenience in that, in order to perform communication connection between the NMS server and the BIU of each relay, the manager should undergo a serious of processes of memorizing IPs respectively registered in the BIUs one by one and registering the memorized IPs in the NMS server. Also, there is a problem in that an error may occur in an IP setup operation of a non-expert.